Closure for containers

ABSTRACT

A closure for a container comprising metallic foil and paper which are bonded together to form the closure. The closure is formed in a punch press to form a number of ridges in the foil which are forced into the mating surface of dampened paper. After the paper dries and shrinks, the ridges are intimately interlocked into the fibers of the paper.

United States Patent Inventor John M. DeVoe Nashville, Tenn. Appl. No.785,429 Filed Oct. 25, 1968 Division of Ser. No. 601,136, Dec. 12, 1966,Patent No. 3,408,902. Patented Jan. 26, 1971 Assignee United StatesTobacco Company New York, N.Y. a corporation of New Jersey CLOSURE FORCONTAINERS 3 Claims, 8 Drawing Figs.

US. Cl 229/43, 229/ 3.5 Int. Cl B65d 43/00,. B65d 5/64 Field of Search229/43, 3 .SMF

[56] References Cited UNITED STATES PATENTS 3,297,225 1/1967 Bransten229/3.5(M.F.) 3,406,891 10/1968 Buchner 229/3.5(M.F.) FOREIGN PATENTS394,222 6/1933 Great Britain 229/3.5M.F.

Primary Examiner-David M. Bockenek Att0rney-Curtis, Morris & SaffordABSTRACT: A closure for a container comprising metallic foil and paperwhich are bonded together to form the closure.- The closure is formed ina punch press to form a number of ridges in the foil which are forcedinto the mating surface of dampened paper. After the paper dries andshrinks, the ridges are intimately interlocked into the fibers of thepaper.

PATENTEU JAN26 1971 3; 558,036

sum 2 0F 2 v VENT J- M.De

ATTORNEYS 711m MW CLOSURE FOR CONTAINERS This application is a divisionof application Ser. No. 60l,l36 filed Dec. 12, I966, now US. Pat. No.3,408,902.

This invention relates to closures for containers and more particularlyto fluid-tight or moistureproof closures formed of layers of paper andmetal foil.

Moistureproof or vaporproof containers have been made by producingcardboard or paperboard containers and lining them with metal foil. Insome of the prior containers the foil lining has been attached to thecardboard by gluing, but that has not proven to be a satisfactory way ofproducing the closures for such containers. A closure in which thelayers are glued together is not sturdy, and it tends to lose its shape,which weakens the closed container, and it also causes the closure tofit less snugly against the container walls then is desired. A tight fitbetween the closure and the container is particularly important in amoistureproof container, and the lid should continue to hug thecontainer tightly even after it has been removed from the container andreplaced on it several times. a An object of this invention is toprovide a container closure that is strong and sturdy, and which fitstightly on the container. A further object is to provide a containerclosure that will retain its desirable characteristics after repeatedremoval from the container and replacement thereon. A further object ofthe invention is to provide a simple and inexpensive method of makingsuch closures. These and other objects will be in part obvious and inpart pointed out below.

Stated in somewhat simplified form, this invention comprises formingcontainer lids from paper and foil layers, e.g., in a punch press, whilethe paper is damp, and in such a way that a number of small, sharpridges or barbed fins are created in the foil against the paper and areforced into the surface of the paper, after which the paper is shrunk.The ridges or fins are intimately interlocked into and are gripped bythe fibers of the paper so that the lid is sturdy and compact. Hence, anintegral lid is formed of the layers of paper and foil without the useof adhesive. 7

IN THE DRAWINGS FIG. 1 is a perspective view, with a portion cut away,of a container with closures made in accordance with the presentinvention;

FIG. 2 is a cross-sectional view of a portion of the container shown inFIG. 1, taken along line 2-2;

FIG. 3 is a cross-sectional view of a punch press for producing theclosure shown in FIG. 1;

FIG. 4 is a plan view of the die portion of the punch press shown inFIG. 3, taken along line 44 in FIG. 3; and,

FIGS. 5 and 6 are similar to FIG. 3, except that they show the punchpress in different stages of its cycle, and they are schematic in thatthey show a single sheet of the paper and foil.

FIGS. 7 and 8 are detailed sectional views of the completed closure.

Referring to FIG. 1 of the drawings, a cylindrical container 2 comprisesa sidewall 4 and end closures 6 and 8. End closure 6 (see also FIG. 2)is in two layers, a paper layer 10 and a metal foil layer 12. Sidewall 4is of similar construction, com prising both a paper layer 14 and a foillayer 16. Each of the layers of closure 6 is a single circular piece ordisc which has been shaped to form a shallow cylinder with a flat,disclike end wall 18 and a cylindrical sidewall formed by portions 19and 21, respectively, of the paper and foil layers. The internaldiameter of sidewall 20 is such that it fits snugly against thesidewall4 of the container. The portion of the sidewall 20 that has beencut away to expose the cylindrical portion 21 of the foil layer 12 isenlarged in FIG. 8, and shows a great many small ridges 22 in portion21. These ridges project into and interengage with the paper layerportion 19, creating a strong bond between the two layers and forming anintegral mechanically-laminated wall.

FIGS. 3 through 6 show the portions of a standard punch press that havebeen adapted to produce closure 6 in accordance with the presentinvention. The punch press 24 includes a fixed die assembly 26 and amovable punch assembly 28 which moves vertically to engage the die 26 asshown in FIGS. 5 and 6.

Referring to FIG. 3, the die assembly 26 includes a shaft 30 upon whichcomponents of the die assembly are mounted. Attached in a stationarymanner to shaft 30 are: a die shoe 32; a center post 34; a circular pad36; and, a peripheral cutting ring 40. Pad 36 presents a flat uppersurface except that it has a raised rim portion which presents anelevated peripheral edge surface 37. Edge surface 37 is an invertedfrustoconical surface so that it slopes toward the center of pad 36.Circular pad 36 is surrounded snugly by a draw ring 38 which hasfrustoconical top surface 39, and (see also FIG. 4) is mountedresiliently in a manner later to be described. Draw ring 38 issurrounded snugly by cutting ring 40, the inner edge of the top of whichis a cutting edge 42.

Draw ring 38 is adapted to slide vertically inside cutting ring 40 alongthe outside of pad 36 and central post 34 with its upward motionlimited, however, by the engagement of a flange 44 on the draw ring witha horizontal edge surface 45 of ring 40. Draw ring 38 is supported by aplurality of rods 48, the upper ends of which are fixed to the drawring, and each of which is rigidly attached at its lower end to a ring49 that slides on shaft 30. A heavy compression spring 50 presses upwardon ring 49 urging draw ring 38 toward the position shown. Spring 50rests upon a disc 51, which is supported adjustably on shaft 30.

The punch assembly 28 of the punch press is located above the dieportion 26 and moves downwardly and engages the die assembly in thecourse of each closure-forming cycle of the machine. Punch assembly 28comprises: a punch head a punch holder 52 which is mounted in a fixedmanner on head 55; and, a punch 54 which has a top flange 57 by which itis rigidly affixed to holder 52 by a clamp ring 56. Punch 54 is acircular ring which is similar to draw ring 38 and has the same generalouter and inner radii except for the flanges 44 and 57. Punch 54 ispositioned above the draw ring and has a bottom frustoconical surface 53which is identical with surface 39 of the draw ring and forms a cuttingedge which mates with cutting edge 42 of the stationary cutting ring 40.As the punch assembly moves downwardly to engage the die assembly, punch54 enters the space between pad 36 and cutting ring 40, and surface 53engages surface 39 so that the continued movement pushes draw ring 38down, overcoming the upward force .of spring 50. Also, as will beexplained below, the cutting edges interengage to cut a disc portionwhich is formed into a closure 6.

Slidably mounted within punch ring 54 and normally resting against punchholder 52 is a punch pad 58, which is of substantially the same radiusas pad 36. Punch pad 58 has a bottom surface which is flat except thatthe edge is somewhat beveled to form a frustoconical edge surface 60that is adapted to mate with the raised edge surface 37 of pad 36. Punchpad 58 is rigidly mounted on a shaft which is surrounded by acompression spring 62 by which the shaft and the punch pad are normallyheld in the position shown in FIG. 3. Punch pad 58 contains a pluralityof air vents 64 which are normally closed by valves 63 which are urgedto closed position by springs 65. However, the vents are opened when theprojecting noses of valve 63 are pressed upwardly.

The sheets of paper 66 and foil 68 from which the closures are producedare drawn through the punch press from left to right with foil sheet 68passing just above the upper surface of die assembly 26 and with thepaper sheet 66 directly above the foil sheet. The paper and foil sheetsare guided in this movement by a metal plate 70 located a short distanceabove the upper surface of the die assembly 26 and forming a narrowhorizontal slot 72, through which the paper and foil sheets pass. Acircular hole 74 in plate 70 is of a size to permit the punch 54 to passthrough it.

In the illustrative embodiment, the foil is a thin steel foil, and thepaper is kraft lined can bottom stock" of .03 inch thickness. Prior tofabrication the paper is softened by soaking it with a light soapsolution. In practice; each day the paper which is to be used thefollowing day is wetted on a rewinder onto rolls which are stored overnight in closed containers. Hence, the paper is relatively soft,although it retains sufficient strength to permit fabrication at acommercially satisfactory rate.

The paper and foil sheets advance step-by-step with each step being fora set distance during the sheet feeding portion of each cycle when thepunch assembly is in the position shown in FIG. 3, and remainingstationary when the punch is engaging the die as shown in FIGS. 5 and 6.

The operation of the punch press is illustrated in FIGS. 5 and 6 and isas follows: As the punch head moves downwardly, punch ring 54 forces thepaper and foil sheets downwardly to cutting ring 40 and thence as thepunch moves past the cutting edge 42 of ring 40 the punch cooperateswith the cutting edge to cut both sheets to produce a circular piece ordisc from each of the sheets. The two discs thus formed are unattachedat this time and by the further cooperative action of the punch and dieassembly they are formed into a container closure. As the punch assemblycontinues to move downwardly, the peripheral portion of each of thesediscs is trapped between the upper surface 39 of draw ring 38 and thelower surface 53 of punch ring 54. However, as the punch continues itsdownwardly motion, forcing the draw ring down before it, the peripheralportions of the paper and foil discs slip between the punch and drawrings and are reformed to a cylindrical form so that they assume avertical position between the inner surface of punch ring 54 and sidewall of pad 36. The forming of the sidewalls of the closure in thismanner produces the foil ridges 22 and they are embedded in the surfaceof the paper, the space between pad 36 and punch ring 54 being onlylarge enough to accommodate the layers in this manner.

The inverted frustoconical edge portion of pad 36 (FIG. 6) cooperateswith the peripheral surface of pad 58 to form the foil into a firmcorner which acts as a rigid rim interconnecting the disclike foilendwall with the cylindrical foil sidewall. The inner surface of thefoil is extremely smooth, with only small lines which are formed by theproducing of the external ridges 22. The forming involves bending theblanks around the raised periphery of pad 36 (see FIG. 5) as the punchring pushes the peripheral portions of the blanks downwardly. Theperipheral portions are held in somewhat frustoconical shape by theclamping action between the punch ring and the draw ring 38, and aregradually drawn into the cylindrical shape. The drag" caused by theaction of the punch ring upon the blanks produces a peripheral tensionupon the central disc portions of the blanks so that they are heldsomewhat taut. At the end of the downward movement of the punch ring,pad 58 cooperates in producing the final smooth comer. It should benoted that FIGS. 5 and 6 are somewhat schematic with respect todimensions and the relative positioning of the parts.

As pad 58 approaches pad 36, the trapped air lifts valves 63 and the airescapes through vents 64. When the punch head reaches the bottom of itsstroke, the pads press the paper and foil layers together. As the punchhead begins its upward motion, the completed closure is pushed from itsposition on pad 36 by the draw ring 38 which moves upwardly with thepunch head and which engages the bottom edge of the cylindrical closurewall and pushes the closure upwardly. Thus, the

completed closure remains within the punch ring 54 beneath the punch pad58 after the disengagement of the die and punch portions of the press.

When the punch ring 54 moves upwardly towards the position of FIG. 3,punch pad 58 is pushed downwardly against the action of spring 62 toeject the closure from the punch ring. This is caused by a knocker" (notshown) driving the central supporting shaft 59 downwardly against theaction of its spring 61. The sheets 66 and 68 of the paper and foil arethen advanced another step frorn their supply rolls, and the punchingand forming operation IS repeate While only one die assembly is shown inthe drawings, it is understood that several such assemblies are mountedtogether on shaft 59, and are operated simultaneously.

Subsequent to the forming of the closure as discussed above, the paperis dried so that it shrinks around the foil liner. The shrinking urgesthe paper fibers in around the ridges '22, and the paper is hardened sothat the closure is an integral sturdy structure. The shrinking of thepaper draws it tightly around the comer edge of: the foil liner in asmooth corner from the flattop surface.

As has been pointed out above, sheet 68 in the illustrative embodimentis thin steel foil. In one particular example, the steel is tin-platedsteel foil of .02 inch thickness. The working of the metal foil produceswork hardening so that it has superior characteristics. Tests indicatethat container closures made with such foil and the paper sheet referredto above are superior to metal lids from various standpoints, includingresistance to shock. Also, such closures are superior from thestandpoint of being thoroughly satisfactory over extended periods of useduring which a closure may be removed from its container and replacedmany times. The thin steel cylindrical wall and .the rigid corner haveresiliency and tend to retain the original shape. The paper providesimpact protection and causes the closure to hug the container wall.

It has been found that hard aluminum foil also gives very satisfactoryresults in place of the steel foil. The invention contemplates thatvarious types of paper board may be used provided they are not waterrepellent or water proof. The illustrative embodiment of the inventionis a closure for small containers which may be used for snuff. However,it is contemplated that the invention includes the production of othercomponents.

I claim:

1. A closure for a container comprising, an endwall portion and aperipheral sidewall portion, said endwall portion comprising coextensivelayers of metal foil and paper and said sidewall portion comprisingcoextensive layers of metal foil and paper which are integral peripheralextensions of the firstmentioned layers of metal foil and paper formingsaid end wall portion, said peripheral extension of said metal foilincluding a plurality of ridges on one surface thereof, said peripheralextension of said paper being in contact with said one surface of saidmetal foil, and said ridges on said one surface being intimatelyinterlocked and gripped by the fibers of the paper adjacent theretothereby to bond said metal foil and paper together.

2. A container closure as described in claim 1 wherein said endwallportion is flat and said sidewall portion is cylindrical.

3. A container closure as described in claim 1 wherein said metal foilis tin-plated steel foil and said paper is kraft-coated paper.

1. A closure for a container comprising, an endwall portion and aperipheral sidewall portion, said endwall portion comprising coextensivelayers of metal foil and paper and said sidewall portion comprisingcoextensive layers of metal foil and paper which are integral peripheralextensions of the first-mentioned layers of metal foil and paper formingsaid end wall portion, said peripheral extension of said metal foilincluding a plurality of ridges on one surface thereof, said peripheralextension of said paper being in contact with said one surface of saidmetal foil, and said ridges on said one surface being intimatelyinterlocked and gripped by the fibers of the pAper adjacent theretothereby to bond said metal foil and paper together.
 2. A containerclosure as described in claim 1 wherein said endwall portion is flat andsaid sidewall portion is cylindrical.
 3. A container closure asdescribed in claim 1 wherein said metal foil is tin-plated steel foiland said paper is kraft-coated paper.